The present invention relates generally to a method and apparatus for discharging the contents of a sealed container and has particular utility in discharging the contents of a test tube, serum collection tube or the like. Tubes utilized for this purpose usually include a silica gel barrier. An anticoagulant is placed in the test tube, then a blood specimen is withdrawn from a patient and placed into the test tube, and finally the test tube is sealed with a resilient closure or stopper which is typically formed of rubber. The test tube and its contents are thereafter subject to temperature variations as well as centrifuging operations. During centrifuging, serum separates from whole blood with the serum positioned above the whole blood within the test tube. The silica gel barrier typically moves between the serum and the whole blood. This, of course, is conventional.
Three different approaches are known for handling the blood within the test tube subsequent to the centrifuging operation. One approach, illustrated and described in U.S. Pat. No. 5,139,174, to Golias, issued Aug. 18, 1992, relates to the removal of the stopper from the test tube and the placing of a dispenser on the open top of the test tube. The dispenser is then squeezed or otherwise manipulated to expel one or more drops of blood onto a specimen plate.
When using this approach, namely, the provision of a dispenser on the open test tube, it is, of course, necessary to invert the test tube prior to discharging blood from the test tube.
There were, of course, potential problems associated with the removal of the stopper from the test tube such as the potential for contamination of the blood and exposure of the laboratory technician to any disease carried by the blood. Upon removal of the stopper, a phenomenon known as aerosoling causes a spray of minute particles from within the test tube to be expelled into the air. There is substantial present concern by the laboratory technician because of potential exposure to the HIV virus, hepatitis and other diseases which may be carried by the blood.
One solution to this problem is presented in application Ser. No. 07/746,413, to Sarrine, filed Aug. 16, 1991, which describes an apparatus for dispensing fluid from a container or test tube. In general terms, two transfer tubes such as cannulas or needles are held relative to a bulb or pump. Both cannulas puncture the rubber stopper or closure of the test tube. One of the transfer tubes acts as a vent between the interior of the bulb and the interior of the test tube. The other transfer tube establishes a fluid flow path from the interior of the test tube, through the bulb, and out onto a specimen plate or the like. To dispense fluid contained within the test tube, the test tube is inverted, so that the fluid covers the ends of the two cannulas. Upon compressing the bulb, air within the bulb is forced through the vent transfer tube and into the test tube. The resulting positive pressure within the test tube forces the fluid through the other transfer tube as previously described.
Another solution to the problem of aerosoling is described in U.S. Pat. No. 5,114,033, issued to Golias on May 19, 1992, wherein a method and apparatus for discharging the contents of a sealed container are described and illustrated. In general terms, a holder containing one or more cannulas or needles punctures the rubber stopper or closure of the test tube. One of the cannulas is connected to a compressible bulb or pump, and a delivery tube is inserted through the second cannula into the interior of the test tube. Then, upon compressing the bulb, air is introduced into the test tube and the contents of the test tube are pressurized and discharged through the delivery tube onto a specimen plate. This approach avoids the need for inverting the test tube since the delivery tube could be inserted to the desired depth depending upon whether serum or whole blood was to be dispensed. However, this approach did require the use of a separate delivery tube, which could increase the complexity and the cost of the apparatus.
Each of the foregoing patents and application are incorporated by reference.